Actuator



May 15, 1956 Filed Jan. 14, 1955 W. GROEN ACTUATOR 4 Sheets-Sheet lINVENTOR: WI LLEM GROEN W. GROEN May 15, 1956 ACTUATOR 4 Shets-Sheet 2Filed Jan. 14, 1953 INVENTOR: WI LLEM G ROEN I ATT'YS May 15, 1956 w.GROEN 2,745,320

ACTUATOR Filed Jan. 14, 1953 4 Sheets-Sheet 5 INVENTOR. WILLEM GROEN BYZATT'YS W. GROEN ACTUATOR May 15, 1956 4 Sheets-Sheet 4 Filed Jan. 14,1953 INVENTOR. W I LLE M G R 0 EN ATT'YS United States Patent ACTUATORWillem Green, Chicago, 111., assigno'r to Gnsrud Machine Works, Inc.,Chicago, 111., a corporation of lllinois Application January 14, 1953,Serial No. 331,233

7 Claims. (Cl. 9G14) This invention relates to milling machines, and hasparticular reference to actuating mechanism for controlling high-speedrouters and drills carried by articulated radial arms for movement toany point upon the surface of a Work-holding bed.

The main objects of this invention are to provide improved actuatingmechanism for raising and lowering the tool-carrying head between aninactive elevated position and a lower operating position; to provide animproved form of mechanism of this kind wherein the operating head isautomatically lifted by power-driven jack mechanism and drops by gravityat a controlled rate to its oper ating position; to provide an improvedarrangement of devices for automatic control of such actuating mechanismby the finger of the operator while his hands are in position'forguiding the milling Work in which the machine is engaged; to provide animproved combination of jack mechanism and dashpot mechanism for raisingand lowering the milling head; and to provide improved means whereby thejack may be selectively adjusted to add force to the descent of themilling head or to otter no assistance.

Ajspecific embodiment of this invention is shown in'the accompanyingdrawings in which:

Figure 1 is a perspective view of a radial arm drilling machineconstructed according to this invention.

Fig. 2 is a front elevation of the drill carrying head of the'device ofFig. 1 with the lever arms of the guide handle shown partly in sectionon the line 22 of Fig. 1.

Fig. 3 is a side elevation of the tool carrying head togetherwithforearm portion of the supporting frame, the latter having its doorplate removed to disclose the actuator mechanism that is housed within.

Figs. 4 and 5 are similar diagrammatic views of the electricallycontrolled valves and pneumatic pipe system for effecting the reversemovements of the jack which actuatcs the mechanism for lifting themilling head.

- Fig.6 is a top plan of the actuator mechanism with some of the relatedparts shown in section.

Fig. 7 is a side elevation of the same with the jack cylinder shown inlongitudinal section.

Fig. 8 is a vertical axial section of the dashpot, taken on line 8-8 ofFig. 6.

Fig. 9 is a horizontal section of the handle which guides the operatingposition of the milling tool, showing the mechanism for push buttoncontrol of the electric switch for the valve control mechanism shown inFigs. 4 and 5.

'ln the-form shown in Fig. 1, the particular form of toolcarryingmilling head and guide arms are of a design suitable for drillingoperations, but it is to be understood that the invention is equallyapplicable to the routers, involving mere changes-in the form of theguiding handles for greater visibility and changed location of theswitch-actuating buttons.

The use of high-speed spindles, for routing and drilling stackedsheets-of non-ferrous metals, is a proven and accepted practice. By thismethod sheets to be cut are stacked on a table and as'm'any templates aspossible are nested side by side on top of the sheets and secured to thetable, allowing spaces between the templates to accommodate the diameterof the pattern follower. It is to this type of machine that the presentinvention is particularly directed. p

In the form shown in Fig. l, the milling head 10 comprises motor and thetool-driving spindle. The head 10 is vertically slidable on a supportingcarrier frame, which comprises horizontally extending arms 11 and 12swingable about a vertical bearing 13, and articulated on one or moreintermediate vertical axes 14, whereby the milling tool which in thedrawings is shown as a drill 15, may have universal horizontal movementto any position over the surface of a table 16 on which the Work that isto be operated upon is clamped or otherwise fastened. The supportingframe is similar for both drilling and routing operations, and thedifference between the routing and drilling structures resides mainly inthe structure of the head 10 and milling tool, with incidental changesin the operating handles and motor speeds.

The actuating mechanism for effecting the up and down movements of thehead 10 is housed within the interior of the hollow forearm member 11 ofthe articulated frame that carries the head.

In the form shown, the front end of the forearm portion 11 has verticalguideways 17 which coact with a guide rib or base member 18 for accuratevertical sliding movement of the head it integrally mounted on themember 18 is a lug 19 that is pivotally connected to a pair of links 2twhich in turn are pivotally connected to one arm of a bell crank lever21 which is pivoted betweenlugs 22 on a base frame 23 within the arm 11.The other arm 21.1 of the bell crank lever 21 is forked to embracetraveler block 24 and has bearings for trunnions 25. The block 24 isslidable on the piston rod 26 of the cylinder 27 of a fluid actuated orpneumatic jack. This cylinder is pivoted by trunnions 23 on spaced lugs28.1 on the base- Also, pivotally mounted on the trunnions 25.

For most operations, this actuating mechanism raises the milling head itto an elevated position by means of the pneumatic jack 27 and thenallows the headli) to descend by gravity at a rate controlled by thedashpot 32. The piston rod 26 of the jack has a fixed shoulder or head34 which en ages the block 24 whenthe piston 35 of the pneumatic jack isriven toward the left of Fig. 7. The rod 26 is freely slidable in theblock 24 so that during reverse movement of the piston 35 the rod hasoverrunning relation to the block 2 3, and the head 34 can shift to theposition 34.1, as indicated by broken lines in Fig. 7, so as to free themilling head 10 to fall by gravity at a speed controlled by the dashpot32.

In order to provide for circumstances in which it might be desirable touse extra pressure to force a drill into the work, by adding the powerof the jack 27 to the weight of the milling head 19, the block 24 isprovided with a set screw 36 that can be advanced from its normalposition to engage an angular groove 37 in the rod 26', thus fixing theblock 24 against sliding on the rod.

As shown in Fig. 8, the dashpot cylinder 32 is closed at both ends byheads 35; and 39, and has slidably mounted therein between said heads apiston 44 which has piston rods 31 and 41 connected to opposite ends ofits hub extensions 42. The piston 43 has a main part 43 forming arelatively large passage with branch passages 44 communicating with thechamber 45 at the right side of the piston. The hub 42 is counterboredon the left 1 5. Such .control valves are well known and readilyobtainable on side of the piston 40 to form a guidewayfor a check of theseat near the right-hand end of the valve 45. v A relatively small bleedport 48 extends axially through the valve 45 and its eifective diameteris controlled by a needlevalve 49 that extends through an axial bore inthe piston rod 31. The stem 5d of the needle valve 49 is adjustablyconnected to the rod 31 by threads 51, and has a knurled head-52 foradjusting the position of the needle. valve 47.

' The cylinder 32 is filled with oil. Its heads 38 and 39 are. providedwith ports 53 and 54 respectively, for injecting and removing the liquidcontents of the cylinder.

The port 53 is closed by plug 55 and the port 54 is closed by a valvedoil cup 56.

The jack cylinder 29 has ports 57 and .58 in its heads for admitting andexhausting air to the chamber at opposite' sides of its piston 35. Theseports are connected to a source of fluid under pressure preferably air,through a system of piping controlled'byfour valves actuated as a unitby electrical means, as illustrated in Figs. 4- and electromagneticallyactuated four-way air the market, and are consequently sutiicientlyrepresented for the purposes of this disclosure by these diagrams.

Fig. 4 shows the relation of the valves and air passages when thecontrol switch is closed, and Fig. 5 shows the relation vthat existswhen the control switch is open.

As shown in these diagrams, the jack cylinder 27 has its left-hand port57 connected to pipe 59 which has one branch controlled by valve 60leading to the air pressure source 61, and a second branch controlled byvalve 60.1 leading to exhaust passage 62. The right-hand port 58 ofcylinder 27, is similarly connected by pipe 63 and its branchesjthroughvalve 64 to the air source 61, and through valve 64.1 to the exhaustmain 62. When the button of switch 65' is in its closed'position, asindicated iniFig. 4, then valves 60 and 64.1 will be open and valves60.1 and 64 will be closed, andthe direction of air flow will be asindicated by arrows in Fig. 4. When the control button of switch 65 isin its normal open position, as in Fig. 5 valves 60 and 64.1 will beclosed and valves 60.1 and 64 will be open, and consequently air will besupplied under pressure to port 58 of jack 27 through will beexhaustedthrough port 57 by pipe Figs. 3 and 9. The lever arms 66 are connectedby-links 69 to a cross head 70 which is guided by parallel vertical rods71, which are longitudinally slidable in the body of the'head 10, asshown in Fig. 2. The crosshead 70 has a hole-finding member 72 locatedin axial alignment with the spindle 73 of the milling head 10, and has abore throughwhich the drill 74 may pass down into the work.

The switch 65, which is preferably a microswitch, is mounted in ahousing 75 carried by the right-hand guide lever 66. The micro-switch isnormally open. The handle bar'68 is hollow and has mounted therein anaxially slid- ;able rod 76, vwhich is aligned with the button 65.1 of

the micro-switch, and is normally urged by compression spring 77 to areleased position. -A control pin 78 extends crosswise through the handbar and has a V-shaped cam notch 79 .in its side positioned to coactwith the V shaped end 80 of the rod 76. The spring 77 tends to bring thepin 78 to a neutral position, as indicated in Fig. 9. When, however, thepin 78 is shifted longitudinally by finger pressure at either of itsends, the cam clips along the side of one of the adjacent levers 66, as'

indicated in Fig. 2, so as to be out of the way.

The operation of the device shown is as follows:

When in use, the motor that drives the spindle of the milling head 10 isin continuous operation and the drill is normally held in a raisedposition except while the switch 65 is held closed. The operator shiftsthe milling head over the work and for drilling seats the tip of thehole finder 72 into a hole inthe template and .thenpresses either end ofthe pin 78 toshiftthe bar 76 and close the switch 65. This. causes thefourway valve to be set, as shown in Fig. 4 to'supply airpressure to.the left-hand end of the cylinder 27, projecting the piston rod. 26 tothe right as indicated by broken lines in Fig. 7. This'leaves themilling head 10 free to descend by gravity at a rate controlled by thedashpot 32. The weight ofthemilling head acting through bell crank lever21 and the piston rod 31 forces the piston 40 to the left of Fig. 8. Theflow of liquid through passage 48 sets the speed at which the millinghead 10 can descend. This flow through the passage 48 is restricted bythe needle 49, and thus can be adjusted by turning the needle forward orback by knob 52. l

When the operator releases the pin 78, spring 77 shifts bar 76 away frombutton 65.1 and the switch opens, cause ing the four-Way valve to'beset, as indicated in Fig. 5, to' admit air pressure at port 58 andexhaust air at port 57 of the jack cylinder 27,:lifting the milling head10 so as to raise the drill 74 and hole finder 72 clear of the work.

Asshown in Fig. 8,. the dashpot 32 offers practically no resistance tothe lifting of the milling head 10, since movement of piston 40 to theright causes the liquid to force the valve 45 away from its seat at theleft-hand end of" the passage 43, and thus opensthat passage to theports 47, permitting a rapid flow of liquid through the piston andconsequent relatively free movement of the piston 40 to the'right.

The milling head 10 is provided with latching means for. locking it inan elevated position when'it is not in use.

This comprises a latch hook '82 pivoted at 83 on the cross head 70, andhaving a shoulder 84 adapted to be hooked over the stud 85 on astationary part of the frame 11; The hook 82 is provided with a cammingsurface 86, which causes it to' ride into position for engagement withthe lug 85; The latch hook 82 is normally urged by'a compression spring87, into position for engagement of the shoulder 84with the lug 85, andis also provided with a trigger arm 88 which is in bell crank relationwith the latch hook 82, and which extends forward where it can be easilyreached by the operator to trip the latch when he isready to put thedevice to work.

An adjustable stop 891imits the normal upward move ment of the millinghead by engaging the motor base mamber'18. This stop can be turned outof the way when the It is to be noted that the'control of the downstrokev speed of the-millinghe'ad by the dashpot 32 avoids the breakingof the drill whenitcomes through the work. Without such control a drill;onpassing through'the work and meeting less resistance, tends to shootthrough while the chip is too strong to be cut easily.

When the mechanism is out of service, the milling head will be held inan elevated position with the latch 82 engaged with the stud 85 of Fig.3, and the parts of the actuating mechanism will be as indicated in Fig.7, except that the slide 24 will be shifted a short distance to the leftof the head 34 of the jack piston rod and the bell crank 21 will betilted slightly further to the left. When the operator is ready tocommence drilling operations, after having turned on the electriccurrent and established pressure in the air line, he releases the latch82 by means of the trigger 88, whereupon the milling head 10 falls ashort distance by gravity until stopped by the engagement of the block24 with the piston rod head 34, where it is held by air pressure at theright of the piston 34 of the jack 27, and the parts of the actuatorwill then be in the position shown in Fig. 7.

In the foregoing description and drawings, the invention is illustratedas applied to a drill. The actuator mechanism is the same for routingmachines, except that the router does not require the hole finder 72 andthe locations of the guide handles and the microswitch are changed togive greater visibility for guiding the router and milling head over thework.

Although but one specific embodiment of this invention is herein shownand described, it will be understood that numerous details of theconstruction shown may be altered or omitted without departing from thespirit of this invention as defined by the following claims.

I claim:

1. In a milling machine, a carrier frame mounted for movement in ahorizontal plane, a milling head vertically slidable on said carrierframe, a fluid actuated jack on said frame having a reciprocatingmember, actuating means interposed between said member and said millinghead for raising said milling head, said reciprocating member having asliding connection with said actuating means and a shoulder foroperatively engaging said actuating means upon movement in the liftingdirection only, said reciproeating member slidably overrunning saidactuating means upon movement in the opposite direction to release thesame for gravitational descent of said milling head, a dashpot actingbetween said frame and head to retard the speed of descent of said head,a source of fluid under pressure, valve means operable for controllingadmission of fluid from said source to said jack and the exhaustingthereof to drive said reciprocating member selectively in oppositedirections, a handle on said frame for guiding horizontal movement ofsaid milling head, and manually controlled means on said handleoperatively connected to said valve means for selecting the direction ofmovement of said reciprocating member.

2. The combination specified in claim 1, wherein the valve means iselectromagentically actuated and the direction of movement of thereciprocating member is determined bythe opening and closing of theelectric circuit by the manually controlled means on the frame handle.

3. In a milling machine, a carrier frame mounted for movement in ahorizontal plane, a milling head vertically slidable on said carrierframe, a fluid actuated jack on said frame having a reciprocatingmember, actuating means interposed between said member and said millinghead for raising said milling head upon movement in one direction, saidactuating means comprising relatively overrunning parts adapted torelease said milling head for solely gravitational descending movementupon a reverse movement of said reciprocating member, a dashpot actingbetween said frame and head to retard the speed of descent of said head,a source of fluid under pressure, and valve means for controllingadmission of fluid from said source to said jack and the exhaustingthereof to operate said reciprocating member selectively in oppositedirections.

4. In a milling machine a carrier fiame mounted for movement in ahorizontal plane, a milling head vertically slidable on said carrierframe, a fluid actuated jack on said frame having a reciprocatingmember, actuating means interposed between said member and said millinghead for raising said milling head upon movement of said member in onedirection, said actuating means comprising a rod connected to saidreciprocating member, a traveler block in which said rod islongitudinally slidable and a shoulder on said rod positioned to engagesaid block for raising and to disengage said block for releasing saidmilling head, said millinghead being released to descend by gravity, adashpot acting between said frame and head for retarding the speed ofgravitational descent of said head, a source of fluid under pressure,and valve means for controlling admission of fluid from said source tosaid jack and the exhausting thereof to drive said reciprocating memberselectively in opposite directions.

5. in a milling machine having a base, a vertically extending supportcolumn, and a horizontally extending carrier arm mounted on said supportcolumn, a milling head vertically slidable in ways mounted on the freeend of said carrier arm and normally urged downwardly by gravity to anoperating position, a fluid actuated double acting cylinder and pistonmounted on said carrier arm adjacent its free end, a bell crankpivotally mounted on said carrier arm on a horizontal axis and having alink on one of its arms pivotally connected to said milling head, a rodon said piston having sliding connection with the other arm of said bellcrank, a fixed shoulder on said rod for engaging said other bell crankarm to operate said bell crank for raising said milling head when bothpiston and rod are moved in one direction, said rod slidably overrunningsaid other bell crank arm when moved in the opposite direction andthereby releasing said milling head to descend by gravity, means foroperating said cylinder and piston in opposite directions selectively,and means for regulating the rate of downward movement of said millinghead.

6. In a milling machine having a base, a vertically extending supportcolumn and a carrier arm mounted on said support column for movement ina horizontal plane, a milling head vertically slidable in ways mountedon the free end of said carrier arm and normally urged downward bygravity to an operating position, a fluid actuated double actingcylinder and piston unit mounted on said carrier arm adjacent its freeend and having apiston rod extending from the piston towards saidmilling head, a. bell crank pivotally mounted on said carrier arm on ahorizontal axis adjacent said milling head and having a link on one ofits arms pivotally connected to said milling head, said piston rodhaving a sliding connection with the other arm of said bell crank, afixed shoulder on said piston rod for engaging said other bell crank armto 0perate the same for raising said milling head when said piston ismoved in one direction, said piston rod slidably overrunning said otherbell crank arm when moved in the opposite direction and therebyreleasing said milling head to descend by gravity, means for regulatingthe rate of downward movement of said milling head, a handle on saidcarrier arm for horizontally positioning said milling head, a valvehaving connections with said cylinder and operable for selectivelydelivering fluid pressure to either end of said cylinder for actuatingsaid piston, and means on said handle operable by the operators handwhile gripping said handle for operating said valve.

7. In a milling machine having a base, a vertically extending supportcolumn and a carrier arm mounted on said support column for movement ina horizontal plane, a milling head vertically slidable in ways mountedon the free end of said carrier arm and normally urged downward bygravity to an operating position, a fluid actuated double actingcylinder and piston unit mounted on said carrier arm adjacent its freeend and having a piston rod extending from the piston towards saidmilling head,

7 a bell crank pivotally mounted on said carrier arm on a horizontalaxis adjacent said milling head and having a link on one of its armspivotally connected to said milling head, said piston rod having asliding connection with the other arm of said bell crank, a fixedshoulder on said piston rod for engaging said other bell crank arm tooperate the same for raising said milling head when said piston is movedin one direction, said piston rod slidably overrunning said other bellcrank arm when moved in the opposite direction and thereby releasingsaid milling head to descend by gravity, meansfor regulating the rate ofdownward movement of said'millinghead, a handle on said carrier arm forhorizontally positioning said milling head, an electromagneticallyactuated valve having connection with said cylinder and operable forselectively delivering fluid pressure to either end of said cylinder,and r push button switch means on said handle having electricalconnection with said valve for'operatingthe same;

References Cited in the file of this patent UNITED STATES PATENTS}734,572 Koester July28, 1903 1,705,957 Braren Mar.- 19, 1929 1,962,524Richards June 12, 1934 1,974,919 Harris et a1 Sept. 25,1934 1,983,438Cushman Dec.,4,'1934 2,026,659 Siebenthaler Apr. '23, 1934 2,170,501

Klamp et al. Aug. 22, 1939

